摘要
通过测定根系参数、土壤结构及其它土壤物理性质，对３～９年的人工剌槐林根系改善紫色土结构的作用进行了定量分析。结果表明：有效根密度（指土壤剖面中１００ｃｍ２截面上对土壤抗冲性有增强效应的≤１ｍｍ径级须根的根数）及根量随土层加深呈幂函数变化，其中有效根密度对土壤结构的改善作用最大。当林龄小于４年时，主要是根系的机械缠绕固定作用。随着林龄的增加，有机质的含量显著增加，这时其改善机理不仅可以通过根系缠绕固定土体的直接作用，还可以通过增加有机质的间接作用，并且后者的作用随林龄的增长而增大。不同林龄根系稳定土壤结构的土层范围与其细根在土壤剖面中的分布特征相一致。
Based on the measurement of roots parameters,soil structure and other soil physical property parameters,a quantitative study on the function of the roots of artificial locust trees(3～9 years)to improve the structure of purple soil was made.The results showed that the fibrous roots less than 1mm in diameter are the most effective in improving the soil physical properties.It decreased with soil depth and could be expressed as a power function.Stabilization of soil structure by roots was mainly mechanical twining of roots when the tree age was less than 4 years.With the increasing of the tree ages,the content of the organic matter increased greatly.At this moment the improving mechanism was not only by direct function of roots,but also by the indirect function of the increased organic matter.And the indirect function was more important with the increasing of tree age.The soil depth of the roots of various tree ages on improving soil structure was consistent with the distributed of fine roots in soil profile.
基金
国家自然科学基金
